The present invention relates to a method of and a system for extracting electrical energy embodied in a capacitive source and concerns more particularly a method of and a system for tapping the electrical energy from the overhead wires of AC power transmission lines.
The presence of electrical energy in the overhead wires of high AC voltage transmission lines has been well known for several years as yet. The tapping of that energy, particularly at remote locations, offers numerous advantages, but technological problems, such as the saturation of the transformers used, have hitherto delayed an economical and reliable extraction of that energy.
The object of the present invention resides in a system and a method which permit to harness such available power from the overhead wires of AC transmission lines. The harnessing of that power presents many advantages and provides for a large number of applications one of which resides in feeding the microwave communication networks usually disposed along lengthy transmission lines. At the present time, the communication and data transmission stations are supplied in power by means of diesel type generators, due to their physical remoteness, which show numerous disadvantages in terms of maintenance, reliability and supply in fuel.
As known in the technique, the overhead wire is that conductor hung up at the head of the pylons supporting the high voltage conductor bundles and which normally acts as a lightning arrester for power transmission lines. That wire is therefore grounded against earth and is not used to convey electrical energy. However, due to its proximity to the bundles of conductors, a certain amount of energy is induced in that wire through capacitive coupling.
The purpose of the present invention is directed to the tapping of that AC energy induced in the overhead wires capacitively coupled to the bundles of conductors of AC voltage transmission lines.